Do I need to reinforce the floor?

[shootingstar]

that is the same size system I was looking at initially.

FWIW
Hubby works in the field so when I mentioned it he got "that look" on his face.....and headed into the office.
After half an hour clacking away on the keyboard and the calculator he came back out and explained just how extensive the renovations to the structure would be.

Our house was built in 98 and is a 4-level side split.

I pondered it for a day or two but eventually decided (for me at least) that it meant crossing that line from obsession to "really ought to be under observation" so I just couldn't do it and modified the plan.

Just my 2 cents, you need to get someone qualified to crunch your numbers and then decide.